There are numerous techniques known for attaching a fluid tube to the wall or end cap of a container such that fluid can be introduced into or directed out of the container. One common technique is to insert the tube through a hole in the wall or end cap and secure the tube such as by soldering, welding, or brazing. This technique is shown in U.S. Pat. Nos. 4,496,378 and 5,048,309. Another technique is to form the tube in the bore such as by outwardly deforming the tube (i.e., swaging). This technique is shown in U.S. Pat. Nos. 4,496,378, 4,291,548 and 4,118,323. A still further technique is to machine the surface of the end cap or wall around the tube bore to provide a collar. The tube is then inserted within the bore, and the collar is coined or crimped inwardly against the tube to secure the tube. This technique is shown in U.S. Pat. No. 4,707,999. This latter technique has become accepted in the refrigeration industry for attaching a pick-up tube to the end cap or wall of a receiver housing. The pick-up tube extends inwardly from the inside, inlet opening of the end cap or wall to draw liquid refrigerant from the receiver.
In certain situations, and in particular in a refrigerant receiver, it is also necessary that a fluid-tight connection be achieved between the tube and the end cap or wall. As such, it is known to form an annular bead on the end of the tube, and locate the bead within a counterbore formed in the end cap or wall. An O-ring type seal is disposed between the bead and the shoulder to fluidly seal the tube in the bore. The tube is then secured to the end cap or wall using one of the techniques described above. This sealing technique is also shown in U.S. Pat. No. 4,707,999, as well as in U.S. Pat. No. 5,191,775.
While the above techniques can be useful in certain situations to attach a tube to a end cap or wall of a container, they are not without drawbacks. For example, in attaching a pick-up tube to an end cap or wall of a refrigerant receiver, machining away the inside surface of the end cap or wall to provide a collar results in wasted material. Crimping or coining the collar into engagement with the tube also requires time and additional machining steps. With aluminum end caps, this technique also typically requires the tube to be attached along or near the center-line of the end cap, such that break-through of the end cap is avoided. Forming the bore at the center-line of the end cap, however, limits the potential applications for the receiver. For example, in some situations it is desirable to mount a plurality of components to the top surface of a receiver end cap. If the pick-up tube bore is formed at or near the center-line of the end cap, the number of additional components mounted to the end cap can be limited. While it is known to form the outlet opening for the bore off-center on the end cap, cross holes must then be drilled transversely through the end cap to connect the outlet opening to the inlet opening along the centerline, and appropriate plugging is then necessary. This further increases the machining steps, labor costs, and wasted material.
Finally, providing an additional O-ring type seal within the bore to provide a leak-tight arrangement further increases material costs, machining steps, and consequently, the overall cost of the refrigerant receiver.
Thus, it is believed that there is a demand in the industry for an effective technique for attaching a fluid tube to the end cap or wall of a container which reduces material waste and machining steps, and provides a fluid-tight seal without an additional O-ring type seal.